On Tue, Oct 4, 2011 at 16:35, Grant Likely wrote:
On Sat, Oct 01, 2011 at 12:39:21PM +0200, Linus Walleij wrote:
2011/9/30 Grant Likely:
I'm not convinced that the sysfs approach is actually the right interface here (I'm certainly not a fan of the gpio sysfs i/f), and I'd rather not be putting in unneeded stuff until the userspace i/f is hammered out.
Actually, thinking about it I cannot see what would be wrong with /dev/gpio0 & friends in the first place.
Using sysfs as swiss army knife for custom I/O does not seem like it would be long-term viable so thanks for this observation, and I think we need /dev/gpio* put on some mental roadmap somewhere.
Agreed. I don't want to be in the situation we are now with GPIO, where every time I look at the sysfs interface I shudder.
the problem with that is it doesn't scale. if i have a device with over 150 GPIOs on the SoC itself (obviously GPIO expanders can make that much bigger), i don't want to see 150+ device nodes in /dev/. that's a pretty big waste. sysfs only allocates/frees resources when userspace actually wants to utilize a GPIO. -mike